A conventional host for industrial use usually is installed in a host cabinet of 19 inches wide to meet the modularized requirement. There is a commonly accepted industrial standard unit 1U which defines a space at the dimension of 19 inches long, 19 inches wide and 1.75 inches high. This standard provides great convenience for modular design and configuration. In response to the requirements of high speed network, the number of hard disk drives in the host increases rapidly. The function of the main board and connection interface also have to expand. Hence many more standards have been developed based on the standard unit 1U, such as 2U and 3U that have the height of 3 inches and 4.5 inches. There are even 4U and 5U specifications that provide more space to accommodate larger hosts.
Whatever the host specifications, design of the power actuation structure always is a troublesome issue. As the switch for controlling ON and OFF of electric power is located on the host circuit board, the present methods generally have a connection line such as the power cord to link electric signals at the front end or rear end of the host. There is a button at the connection juncture of the power cord to control ON and OFF. However, if the button is located at the front end of the host, as the front end of the host is fully occupied by the retrieval electronic devices such as hard disk drives or optical disk drive, there is no enough space to accommodate the power cord. Hence the current practice is to install the button at the rear end of the host. While such an approach overcomes the wiring and space constraints, the rear end of the host generally is close to the wall. Hence users have to move the host every time to set the button ON or OFF. In the event that a whole set of hosts are mounted in a cabinet, to move the entire cabinet could become an overwhelming task for one operator. Moreover, wiring and covering of the power cords also are difficult. Thus how to improve power actuation structure is an issue pending to be resolved.